This invention relates to a bicycle lock consisting of a combination lock and a length of steel cable or chain connected with the ends of said lock.
The combination lock employed herein is novel in its construction. A shaft is rotatably arranged within the casing of the lock. One end of the shaft is secured to a knob and a numeral wheel which are formed in one body. Three step wheels, each having a recess in its periphery, are loosely mounted on the shaft. The locking bolt inserted in the casing is provided with three notches each corresponding to one of the step wheels. When at least one of the step wheels engages with a notch, the bolt cannot be withdrawn from the casing.
For unlocking, the knob is first turned clockwise until the first numeral of the code number appears in a window provided in the casing, whereby the first step wheel which is farthest from the numeral wheel is brought to the release position wherein its peripheral recess lies just above the corresponding notch of the locking bolt; next, the knob is turned counterclockwise until the second numeral of the code number appears two times in the window whereby the second step wheel is brought to the release position wherein its peripheral recess lies just above the corresponding notch of the locking bolt, and finally the knob is turned again clockwise until the final numeral of the code number is visible in the window whereby the third step wheel adjacent to the numeral wheel is brought to the release position wherein its peripheral recess lies just above the corresponding notch of the bolt. Then as all the step wheels disengage from the notches of the bolt, the bolt may be withdrawn from the casing.
It is to be noted that this invention provides against accidental movements of the first and the second step wheels. For this purpose, a double clip disposed in the casing is thrust on the flanged portions of the first and the second step wheels so as to hold them immobile. Since the positions of the step wheels are not disturbed, unlocking operation can be positively effected notwithstanding vibration or shock.